Process of treating organic esters of cellulose



Patented Nov. 3, 1936 UNITED STATES PATENT OFFICE PROCESS OF TREATINGORGANIC 'ESTERS OF CELLULOSE Alma Dobry, Paris, France, assignor toCompagnie de Produits Ghimiques et Electrometallurgiques, Alais, Frogcset Camargue, Paris, France, a corporation of France No Drawing.Application January 24, 1935, Serial No. 3,364. In France February 21,1933 6 Claims. (Cl. 1854) The present invention relates to a method ofform of an even sheet on a solid surface, either treating organic estersof cellulose, which is movable or not, and will furnish, aftercoagubased on a property of said bodies that was not lation in a bath ofwater, a film which can be known up to the present time and thereforewas used as a support for photographic gelatine. Or

never used for practical purposes. This propagain a vegetalor metallicfabric canbe impreg- 5 erty is the solubility of these bodies in theaquenated with the solution of cellulose acetate and ous solutions of agreat number of metallic salts subjected to the action of water, whichwill proof perchloric acid. duce ultra-filter membranes. Ordinary paperCellulose acetate, of the composition generor filter paper can also betreated in the same 10 ally employed in the art (soluble in acetone), ismanner. They will thus be strengthened and e soluble in the cold statein concentrated and made watertight, which will make it possible toneutral aqueous solutions of the perchlorates of obtain eitherreinforced filter paper or parchberyllium and of aluminium, and in thoseof ment paper resisting the action of water. The magnesium, calcium,lead (neutral or basic applications of the process according to thepresl5 salt), copper, zinc, strontium, barium, lithium. ent inventionare not limited to the examp The solutions remain sufficiently fluid inthe cold above stated.

state up to a concentration of cellulose acetate Such perch o aSolutions y be ed W of about 15%. At a higher temperature, the oneanother before coagulation. For instance, concentration can be furtherincreased. I may miX perehlorevted Solutions of diaeetyl- Primarycellulose acetate, or triacetate, is not Cellulose, oftriecetyleellulose and of cellulose, 2 directly soluble in solutions ofmetallic perchloin such manner as to obtain a mixed pro rates. But if itis previously dissolved in a solthe cost of which is lower than that ofp vent, such as methyl formiate, and if the oluacetylcelluloses. (Theperchlorated solutions of tion thus obtained is mixed with an aqueous socellulose have been described in my U. S. patent lution of beryllium oraluminium perchlorate, application 712,059 filed February 25 the acetateremains in the dissolved state and 1934, now Patent 2,022,539 of Whichthe present the mixture can be freed from methyl formiate, applicationis a Continuation in p I y without precipitating. It is thus possible,through also incorporate with the perchlorated solutions an indirectmethod, to dissolve triacetate in vari us nit n u p du t su s gelatine,

perchlorates. fibroin, natural silk. These mixed solutions, 30

The perchlorated solutions thus obtained, wh n ooaeulated. y means f wr, r in either of cellulose diacetate (acetate soluble in to theexamples ab Stated. yield new P acetone), or of triacetate, coagulateinstantan ts i W h the presence of the it nous neously by contact withwater and the organic matter ensures the p p of being e ea y ester ofcellulose is regenerated, without any dyed than purely oellulosioproducts a nearly 35 alteration. Furthermore, the coagulation baths aseasily dy as W001 Silk, though h ess containing perchlorate regenerate,by mere expensiveevaporation, Without any loss, the solvent ready Of cfor e particular pl it is to dissolve again a new amount of cellulosicadvisable to determine the nature of the p product, and so on. chloratethat gives the best results, and also the 40 The properties that havejust been described b st condit ons of Wor ing. The following specan beapplied in many ways to industrial cific process s will now be given yWay of manufactures or operations. For instance, the examp solution ofcellulose acetate can be forced Erwmple 'mmes of commercial throughpieces provided with fine holes and imcellulose acetate soluble inacetone are dissolved 45 mersed in a bath of water; the celluloseacetate in 100 kilogrammes of a saturated solution of then coagulates inthe form of a thread which, magnesium perchlorate as pure as possible.after washing and drying, will furnish artificial After homoge asolution is obtained which silk or artificial horse-hair. precipitatesimmediately, under the action of The solution of cellulose acetate canalso be water, regenerating the acetate, and which can be 50 forcedthrough a narrow slot immersed in water utilized for the obtainment oftransp fi s and will thus furnish, after washing and dryor artificialsilks. ing, a strong thin sheet, adapted to be used, for Example II.2kilogrammes of gelatine are instance, for fine wrappings. Or again thesomixed with 500 litres of a saturated solution of lution of celluloseacetate will be poured in the magnesium perchlorate. After dissolutionof the 55 gelatine, kilogrammes of cellulose diacetate are addedthereto. The solution thus obtained can be used for manufacturingartificial textiles having dyeing properties more advantageous thanthose of cellulose acetate alone.

Cellulose formiates and acetoformiates are also very easily dissolved insaturated aqueous solutions of metallic perchlorates and more especiallyin solutions of magnesium perchlorate. These solutions precipitate veryeasily under the action of water, giving threads or films which possessinteresting mechanical properties. The solutions of cellulose formiatethus obtained can be employed, either alone or mixed with solutions inperchlorate of cellulose acetate or of cellulose, in all the knownfabrications that make use of cellulosic solutions, such as thepreparations of artificial textiles, of thin films for wrapping orphotography, of tulles, artificial leathers and so on.

Example HI.-5 kilogrammes of cellulose formiate are mixed with 50 litresof a saturated solution of magnesium perchlorate. After homogenizing andfiltering, the solution that is obtained can be employed for themanufacture of artificial silk by means of known apparatus, use beingmade, as coagulation bath, of water or saline solutions.

The diluted solutions of metallic perchlorates that remain afterprecipitation of the organic esters of cellulose can be easilyconcentrated again by evaporation, with extremely low losses, so thatthey can be reutilized for subsequent operations. Precipitation can alsobe obtained by utilizing, instead of water, other coagulation baths suchas saline or acid solutions which modify the characteristics of theproducts obtained.

What I claim is:

1. A process of treating an organic ester of cellulose, which comprisesforming a solution of said ester in a concentrated aqueous solution of ametallic perchlorate, and treating with a liquid adapted to cause theseparation of the perchlorate from the organic ester of cellulose.

2. A process of treating an organic ester of cellulose of the typesoluble in metallic perchlorate, which comprises substantiallydissolving the same directly in a concentrated aqueous solution of ametallic perchlorate, and precipitating the organic ester of celluloseby means of a liquid from the solution thus obtained.

3. A process of treating an organic ester of cellulose, which comprisessubstantially dissolving the same in a concentrated aqueous solution ofberyllium perchlorate, and precipitating the organic ester of celluloseby means of a liquid from the solution thus obtained.

4. A process of treating an organic ester of cellulose, which comprisessubstantially dissolving the same in a concentrated aqueous solution ofaluminium perchlorate, and precipitating the organic ester of celluloseby means of a liquid from the solution thus obtained.

5. A process of treating an organic ester of cellulose, which comprisessubstantially dissolving the same in a concentrated aqueous solution ofmagnesium perchlorate, and precipitating the organic ester of celluloseby means of a liquid from the solution thus obtained.

6. A process of treating an organic ester of cellulose, which comprisessubstantially dissolving the same in a concentrated aqueous solution ofa metallic perchlorate, and precipitating the organic ester of celluloseby means of water from the solution thus obtained.

ALMA DOBRY.

